Centrifugal fan for blowers.



J. FROELICH.

CENTRlFUGAL FAN FOR BLOWERS.

APPLICATION FILED AUG.5, 1916.

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5 a a a a r JOHN FBOELICH, OF ST. PAUL, MINNESOTA.

GENTEIFUGAL FAN FOR BLOWERS.

Specification of Letters Patent.

Patented Oct. 22, 1918.

Application filed August 5, 1916. Serial No. 113,304.

To all whom it may concern:

Be it known that I, JOHN FRoELrcH, a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented new and useful Improvements in Centrifugal Fans for Blowers, of which the following is a specification. I

y trifugal fans which draw air in axially and discharge it circumferentially.

Its object is to provide a fan of this kind having improved vanes, adapted to promote efficiency, in a strong and durable structure which is free from vibration and noise less in operation. V

In the drawings, Figure 1 is a transverse sectional view of a blower equipped with a fan embodying my invention; Fig. 2 is a longitudinal sectional view taken on the line 2'2 of Fig. 1; Fig. 3 is a detail perspective view of a portion of my pre erred fo m of vane; Fig. 4; is a transverse sectional view thereof; and Fig. 5 is a transverse sectional view of a modified form of vane.

Referring to the drawings, I have used the reference letter A to indicate a blower casing of usual design, having an inlet opening 10 at one side and a discharge opening 11 at the top. A support 12 for said casing is supplied with bearings 13 in which my fan B is revolubly mounted. Said fan B consists of a disk 1 1, which is axially mounted upon a drive shaft 15, and a plurality of spaced vanes 16 secured at their inner ends upon the disk 14 and arranged about the axis of said disk like a skeleton cylinder with one open and one closed end. The outer ends of said vanes 16 are preferably braced or supported by means of the ring 17 secured thereto. The open end of this cylindrical fan B registers with the inlet opening 10 in the casing A and air is drawn through said opening into the fan. The drive shaft 15 is revoluble in the bearings 13 on the casing support 12 and a pulley 18 or other suitable means is supplied to turn said shaft. Each vane 16 is a trough -shaped structure comprising two blades 19 and 20, each of which has flanges.

21 turned back from its ends. Said blades are preferably formed from a single strip of sheet metal by folding said strip longitudinally. The flanges 21 provide means for securing the vanes to the disk 14 and invention relates to that type of can ring 17 upon which they are arranged so thattheir apices point inward toward the axis of the fan. The blade 19 of each vane 16 is inclined forward in the direction of rotation and may be curved (Fig. 5) or bent at an angle (Fig.4), if desired, While the other blade 20 lies in a plane passing through the axis of the fan. The ports between the vanes, therefore, have contracted by centrifugal force, said air being constantly replaced by air which is drawn ax ially into the fan through the opening 10 in the casing A. The formation of the contracted openings between the vanes and the forward inclination of the blades 19 results in forcibly discharging air from the fan at a rate of speed considerably greater than the peripheral movement of said fan and in a direction substantially tangential there to. My fan, therefore, is particularly adapted to high pressure use and the form of the vanes also results in a durable non-vibrating structure.

Having described my invention, what I claim as new and desire to protect by Letters Patent, is:

1. In a fan, a rotary member, a plurality of trough-shaped vanes secured at their ends upon said member and arranged in spaced parallel relation about the axis thereof, each vane comprising a pair of integral blades, one blade resting in a plane passing through the axis of rotation and the other inclined forward from a line of fold in the direction of rotation, the ports between adjacent vanes constantly diminishing in width from the internal margin of the port to its peripheral margin.

2. In a fan, a rotary member, a plurality of inturned trough-shaped vanes secured at their inner ends upon said member and arranged in spaced relation about the axis thereof, each vane comprising a pair of integral blades, one blade resting in a plane passing through the axis of rotation, and

was es the other inclined forward in the direction of rotation, and a supporting ring secured to each blade at the outer ends of said vanes.

3. In a fan, a rotary member, a plurality of trough-shaped vanes secured at their inner ends upon said member and arranged in spaced relation about the axis thereof, each Vane comprising a pair of integral blades, one blade resting in a plane passing through the axis of rotation, and the other inclined forward in the direction of rotation, the peripheral margins of said blades being equidistant from the axis of rotation.

i. In a fan, a rotary member, a plurality of trough-shaped vanes secured at'their ends upon said member and arranged in spaced relation about the axis thereof, each vane comprising a pair of integral blades, one blade resting in a plane passing through the axis of rotation, and the other inclined forward in the direction of rotation, the peripheral margins of said blades being equidistant from the axis of rotation, and the ports between adjacent vanes gradually diminishing in WldtlilfIODl their internal niargins to their peripheral margins.

Whereoi, 1 have hereunto subscribed my name to this specification.

JOHN. FROELIGH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Batents, "Washington, 3. E. 

